Beta-Sitosterol, a main dietary phytosterol found in plants, may have the potential for prevention and therapy for human cancer. (PMID: 146129380 ). Phytosterols are plant sterols found in foods such as oils, nuts and vegetables. Phytosterols, in the same way as cholesterol, contain a double bond and are susceptible to oxidation, and are characterized by anti-carcinogenic and anti-atherogenic properties. (PMID: 13129445 , 11432711 ). beta-sitosterol is a phytopharmacological extract containing a mixture of phytosterols, with smaller amounts of other sterols, bonded with glucosides. These phytosterols are commonly derived from the South African star grass, Hypoxis rooperi, or from species of Pinus and Picea. The purported active constituent is termed beta-sitosterol. Additionally, the quantity of beta-sitosterol-beta-d-glucoside is often reported. Although the exact mechanism of action of beta-sitosterols is unknown it may be related to cholesterol metabolism or anti-inflammatory effects (via interference with prostaglandin metabolism). Compared with placebo, beta-sitosterol improved urinary symptom scores and flow measures. (PMID: 10368239 ). A plant food-based diet modifies the serum beta-sitosterol concentration in hyperandrogenic postmenopausal women. This finding indicate that beta-sitosterol can be used as biomarker of exposure in observational studies or as compliance indicators in dietary intervention studies of cancer prevention. (PMID: 14652381 ). beta-sitosterol induces apoptosis and activates key caspases in MDA-MB-231 human breast cancer cells. (PMID: 12579296 ).

This compound belongs to the class of organic compounds known as stigmastanes and derivatives. These are sterol lipids with a structure based on the stigmastane skeleton, which consists of a cholestane moiety bearing an ethyl group at the carbon atom C24.